BOSTON -- Activists angered by President Bush's decision to send 21,500 more troops to Iraq rushed Thursday to organize protests from New York to San Francisco.

In New York's Times Square, protesters intended to gather at a military recruiting center. Small rallies were also planned across the Boston area, California and in other cities.

Antiwar activists have marshaled more than 100,000 protesters at U.S. rallies on a few occasions since the run-up to the invasion. But the vast majority have been far smaller than those of the Vietnam era.

Political scientists say that's because the draft has been eliminated and because the antiwar movement appears more willing to work within the political system -- a sharp contrast from the 1960s, when many protesters regarded the system as corrupt.

Thursday's protests were cast as a prelude to a bigger gathering starting Jan. 27 in Washington, where demonstrators plan to urge Congress to stand up to Bush, said Hany Khalil, a spokesman of United for Peace and Justice.

The protest will culminate with a day to lobby congressmen.

During the Vietnam War, tens of thousands of demonstrators took part in rallies to demand an end to American involvement in the conflict.

But protests are more accepted now, so they are less shocking to mainstream America, said historian Katherine A. S. Sibley, who teaches about the antiwar movement at Saint Joseph's University in Philadelphia.

"They don't have to be in your face, so they're less noticeable," she said. "Now we have people all over the Net."

And colleges campuses, which were the epicenter of Vietnam protests, are quiet. Antiwar leaders acknowledge that the lack of a military draft leaves the Iraq war protests without the same urgency as Vietnam.

The Iraq war "would end overnight if they tried to do a draft," said Gordon Clark, a spokesman for the antiwar group Peace Action.

Instead, Democrats took over Congress in the last election "and people are already assuming the war's not going to last long," Sibley said.